Compress Image to 100 KB

A 100 KB cap turns up on document and form uploads — ID scans, certificates, proof-of-address photos, profile pictures on government and university portals — and some email systems, help-desk forms and chat tools reject or slow down larger attachments. Phone photos are typically 2–5 MB, so they need shrinking by a factor of 20 or more. This tool hits the limit while keeping as much quality as possible, entirely in your browser: nothing is uploaded and files never leave your device.

How to use this tool

1. Add the photo or scan (or a batch of them).
2. Leave the maximum at 100 KB or type the limit from the form.
3. Optionally set a max width/height or exact pixel size, and choose JPG, WebP or PNG.
4. Download the compressed file (or all of them as a ZIP) and check the size shown.

Formula

size(q, w × h) ≤ limit, solved by binary search on q from 50% to 92%; if the lowest q still overshoots, the dimensions are scaled by ≈ √(limit ÷ size) and the search repeats.

File size grows roughly with the number of pixels, so halving both width and height cuts the size to about a quarter. That is why a photo is first resized to a sensible size — text on a scanned page stays readable at around 1,200–1,600 px on the long side — before quality is lowered.

Example

A 4032 × 3024 phone photo of a certificate (3.1 MB) with max width/height 1,600 px and a 100 KB limit: the photo is resized to 1600 × 1200, then the quality search settles on the highest setting that stays under 100,000 bytes, typically somewhere around 60–75% for a page of printed text.

Documents versus photos

Scanned pages compress well because most of the page is plain paper. Make sure the scan is evenly lit and cropped to the page edge; shadows and wood-grain backgrounds waste bytes. If text looks blurry, raise the max width rather than the quality.